it's not the cancer that kills you, it's the dangerous Cancer drugs. Ivermectin is the ingredient that gives them any efficacy, at all.
https://www.frontiersin.org/articles/10.3389/fphar.2021.717529/full
https://wentworthreport.com/ivermectin-and-cancer/
https://i2b.us/anti-parasite-drug-ivermectin-shows-promise-against-cancer/
https://www.naturalnews.com/2022-04-15-ivermectin-cancer-cure-nine-studies-conclude.html
Or related to infection by parasite, meaning presence of parasite weakens or impacts immune system such that cancer cells aren't disposed of normally.